The present invention relates to a process for producing a polyurethane foam. More specifically, the present invention relates to a process for producing a polyurethane foam, which can be suitably used as heat insulating materials for construction materials, electric refrigerators, refrigerated warehouses, baths and the like, interior materials for automobiles, and the like.
A rigid polyurethane foam has been used as a heat insulating material for construction materials, electric refrigerators, refrigerated warehouses, baths, pipes, and the like since the rigid polyurethane foam is excellent in heat insulating property.
When a polyurethane foam is used, for instance, as a heat insulating material for a construction material for houses, buildings and the like, the polyurethane foam is produced by such a process comprising mixing components containing a polyol as a main component with components containing a polyisocyanate as a main component spraying the mixture to an objective site such as a wall surface or a ceiling under construction of houses, buildings and the like by a spraying machine to foam, and curing the foam.
As described above, when the polyurethane foam is allowed to foam and cured, distinctively strong odor due to the employed catalyst makes the working surroundings undesirable, and the unreacted catalyst remains in the polyurethane foam even after molding, so that there arise some problems such as odor and fogging. Recently, there has been proposed to use 6-dimethylamino-1-hexanol as a catalyst for producing a polyurethane which would little cause odor and fogging (Japanese Patent Laid-Open No. Sho 62-115017).
However, in the production of the polyurethane foam, when 6-dimethylamino-1-hexanol is used as a catalyst, it takes a long period of time for the production because of low reactivity at low temperatures between the polyol component and the isocyanate component which are used in the production of the polyurethane foam, nevertheless the problem regarding odor is solved. Particularly, when spraying is employed for foaming to cure, there arises a problem such as dripping, and there is a defect that its dimensional stability would be decreased at low temperatures because the heat generated during the production of a polyurethane foam is dissipated to the open air, so that the reaction is less likely to proceed, thereby lowering compression strength.
An object of the present invention is to provide a process capable of rapidly producing a polyurethane foam being excellent in dimensional stability even under the surroundings of low temperatures, with little generation of odor due to a catalyst.
According to the present invention, there is provided a process for producing a polyurethane foam comprising reacting a polyol component with an isocyanate component in the presence of a catalyst comprising a compound represented by the formula (I): 
wherein p is an integer of 4 to 8, and a compound having a primary amino group and a tertiary amino group in its molecule, a blowing agent and a surfactant.